Hydrothermal vents found on Mars raise hope in search for life

Earth's hydrothermal vents, where life may have started, face new threats

Hydrothermal vents found on Mars are around 3.8 billion years old, dating from a time when life was emerging on Earth. If similar conditions existed on Mars at that time, it raises the possibility that life took hold on the red planet as well. (NASA)

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Bob McDonald

Bob McDonald is the host of CBC Radio's award-winning weekly science program, Quirks & Quarks. He is also a science commentator for CBC News Network and CBC TV's The National. He has received 12 honorary degrees and is an Officer of the Order of Canada.

The volcanic features are around 3.8 billion years old, dating from a time when life was emerging on Earth. If similar conditions existed on Mars at that time, it raises the possibility that life took hold on the Red Planet as well.

Hydrothermal vents are hot springs on the ocean floor, where warm water oozes up through cracks in the crust of the Earth, bringing with it a rich soup of minerals and chemicals.

Bacteria in the water thrive on these minerals through a process of chemosynthesis. This is similar to photosynthesis used by plants on land, but rather than using sunlight as the source of energy, the bacteria in seawater use hydrogen sulphide from the vents and chemically transform it into nutrients and organic matter. These bacteria form the basis of a food chain that supports a wide variety of creatures such as shrimp, crabs and odd looking tube worms that can reach more than two metres long.

No sunlight required

The vents are independent ecosystems that do not rely on the energy of the sun. So if a catastrophe, such as an asteroid strike were to wipe out life on the surface, there is a good chance these oases at the bottom of the oceans would survive.

Some biologists believe that hydrothermal vents could even be the origin of life on the planet, since they seem to bridge the gap between a chemical non-living world and biology. Their location in deep water would also have protected them from harmful radiation from the sun that bathed the Earth in the early days before there was an ozone layer in the atmosphere.

If these vents are the way life takes hold on a planet, there are lots of other places where that could have happened, such as the surface of Mars, or oceans under the icy crusts of moons such as Europa and Enceladus. That is an exciting proposition, although it means that our first encounter with alien life is more likely to look like a tube worm than little green men driving flying saucers.

Hydrothermal vents, like this one along the Arctic Mid-Ocean Ridge, are hot springs on the ocean floor, where warm water oozes up through cracks in the crust of the Earth, bringing with it a rich soup of minerals and chemicals that can fuel entire ecosystems. (R.B. Pedersen/University of Bergen, Norway Centre for Geobiology)

If hydrothermal vents were involved in establishing life on Earth, then these systems are very old. They are also rare. Only about 500 to 600 are known.

That is why extreme care must be taken as new creatures are intruding on these oases — humans with mining equipment.

Mining threat

It turns out the minerals coming out of the vents, such as zinc, nickel and copper, are highly valued by our high-tech industries. And mining companies are anxious to dredge them up.

'It would be the equivalent of trying to strip mine in the middle of Banff National Park without disturbing the bears.'- Bob McDonald

The mineral resources at the bottom of the ocean are vast, but bringing them to the surface involves disturbing the ocean floor in ways that could threaten the life around the vents. Specialized dredgers, pumps, crawlers, drills, platforms, cutters and corers would dig into the crust and pump materials to the surface.

That same equipment could also dredge up any animals living on the bottom, or cover them in plumes of dust thrown up by the operations. It would be the equivalent of trying to strip mine in the middle of Banff National Park without disturbing the bears.

There would obviously be a disruption in the ecosystem, but how much is too much?

Regulators, such as the International Seabed Authority, are scrambling to put global regulations in place to ensure these operations take place in sustainable ways.

Whether or not hydrothermal vents were the foundation of life on Earth and possibly other worlds, their value lies in their unique place in the ecology of the planet. They demonstrate an alternative way of living that could be the type of alien life we may encounter elsewhere in the universe.

Their precious value should be considered higher than that of the precious metals that accompany them.